[polymer] fix editor hints -- query/queryAll and unused imports

pkg/polymer/test/entered_view_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library polymer.test.entered_view_test;
 
 import 'dart:async';
 import 'dart:html';
 import 'package:polymer/polymer.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 22 matching lines @@
 main() => initPolymer().run(_tests);
 
 _tests() {
   useHtmlConfiguration();
   Polymer.register('x-inner', XInner);
   Polymer.register('x-outer', XOuter);
 
   setUp(() => Polymer.onReady);
 
   test('element created properly', () {
-    XOuter outer = query('x-outer');
+    XOuter outer = querySelector('x-outer');
     outer.expand = true;
     return outer.onMutation(outer.shadowRoot).then((_) {
       // Element upgrade is also using mutation observers. Wait another tick so
       // it goes before we do.
       return new Future(() {
-        XInner inner = outer.shadowRoot.query('x-inner');
+        XInner inner = outer.shadowRoot.querySelector('x-inner');
         expect(inner.enteredCount, 1, reason: 'enteredView should be called');
       });
     });
   });
 }